The overall objectives of the subject contract is to develop a long life, highly reliable, efficie miniature thermal energy system to actuate cardiac assist and total heart replacement devices. The planned activities for the next contractual period include a broad program of system life tests, component reliability tests, engine/actuator development, and some in vivo test support. Specifically, the five task workscope includes: life test systems 4, 5, and 6; test component life and reliability; develop engine and actuator modules; in vivo testing support; and Program Mamagement and Reporting. A twenty-four month program is planned.